双酶法水解酒糟生产调味品的研究

以黄酒酿造副产物酒糟为主要原料，以酸性蛋白酶和葡萄糖淀粉酶为水解剂，对酒糟的水解条件进行正交试验研究。结果表明，酒糟的最佳水解条件为：酸性蛋白酶和葡萄糖淀粉酶按1：1．3的比例，加酶总量为0．08g／100g酒糟，水解温度为45℃，pH值为3．5，水解时间为10h，酒糟和水的固液比为1：3。在此条件下，经酶解、过滤、浓缩至酒糟相等质量的水解液，其总可溶性固形物和氨基态氮含量分别为9．0％和0．560％。     

调配和杀菌条件对酒糟鱼品质的影响

为缩短酒糟鱼的生产周期,采用调配法制作酒糟鱼.研究调配工艺和杀菌温度对酒糟鱼品质的影响.结果表明,酒的品种、蔗糖用量、浸泡温度和杀菌温度对酒糟鱼的理化成分含量、色泽、质构特性和感官品质具有重要影响.将腊鱼于10%蔗糖黄酒溶液(1:1,w/v)中10℃浸泡24 h,真空包装后115℃灭菌30 min,所制作的酒糟鱼品质最好.     

废弃白酒糟酸水解工艺的优化

以废弃白酒糟为研究对象,利用正交实验考察了混和酸浓度、时间和温度对酒糟酸水解效果的影响,以木糖浓度和还原糖浓度为评价指标优化工艺条件,并探索最佳的超声波预处理条件.结果表明,在常温条件下,以500W功率、超声波预处理酒糟10min时酸水解效果更佳.最优的酸水解条件为混合酸浓度为2.5％、水解时间为2.5h,温度为120℃.该条件下,木糖浓度和还原糖浓度达到651.62μg/mL和11.85mg/mL.     

黄酒糟的成分分析和开发调味品可行性的研究

黄酒糟是黄酒生产企业的主要副产物。我国有500多家黄酒企业,每年生产大量的黄酒糟。目前,黄酒糟主要用来做饲料,其综合利用还存在较大问题,附加值不高,限制了黄酒企业效益的提高。本文分析了无锡两家黄酒企业的酒糟样品的水分、淀粉、蛋白质、氨基酸和风味成分,并与黄酒进行了对比,总结了黄酒糟中主要的微生物,在进行以上研究的基础上,论证了黄酒糟开发调味品的可行性。结果表明,黄酒糟是开发调味品的理想原料。     

提高糟烧白酒产品质量和出酒率的探讨

糟烧白酒是生产黄酒的副产物-酒糟,经湿热作用蒸馏而得的酒精饮料。产品主要成份来自黄酒发酵醪经压榨后的糟粕截留下来的酒精等成份或酒糟经二次固态发酵时,加上残存微生物所分泌的各种酶类水解残余淀粉、蛋白质及酒精、乳酸等先液态后固态两次发酵作用的结果。加强科学研究,不断总结经验教训,是提高和进一步提高产品质量及出酒率的唯一途征。     

蛋白酶水解糯米酒糟的工艺优化

分别采用酒用酸性蛋白酶、木瓜蛋白酶水解糯米酒糟,优化提高水解液中氨基态氮含量的工艺条件。不同蛋白酶的水解实验结果表明,酒用酸性蛋白酶的水解效果最理想。糯米酒糟水解的最优条件为:加酶量2 000 U/g酒糟、料液比1∶3、pH3.5、温度40℃、时间5 h。在此工艺条件下,水解液中氨基态氮含量达到0.75 g/L,比初始糯米酒糟液提高了368.75%。     

以白酒酒糟为原料发酵产丁二酸

以白酒酒糟为原料,经酶法糖化,由Actinobacillus succinogenes发酵生产丁二酸。纤维素酶或糖化酶分别水解白酒糟,在酶反应的最适温度和pH条件下,酒糟中的纤维素和淀粉的水解率分别为44.04%和92.26%,相应还原糖对酒糟的得率分别为110 mg/g和126 mg/g酒糟;但2种酶以分步或同步方式水解白酒糟时,酶水解反应受到产物抑制作用,总还原糖得率仅约为150 mg/g酒糟。采用分步糖化发酵工艺,400 g/L白酒糟经两种酶水解后,得到还原糖58.4 g/L,该水解液发酵产丁二酸28.8 g/L,丁二酸产率72 mg/g酒糟;而采用先用纤维素酶水解白酒糟,再用糖化酶和A.succinogenes同步糖化发酵的工艺,240 g/L白酒糟产丁二酸浓度为32 g/L,产率133 mg/g酒糟。以白酒酒糟为原料发酵生产丁二酸,利用了废弃物,无需外源添加氮源,无需对原料进行酸碱预处理,具有一定的应用前景。     

嗜热拟青霉糖化酶的性质及其在黄酒酿造中的应用

研究嗜热拟青霉糖化酶(PtGA15)酶学性质,并探讨了其在黄酒生产中的应用潜力。结果表明,PtGA15的最适pH值为5.5,最适温度70℃,在pH 4.5～6.5范围内、60℃及以下保持较高酶活,对金属离子的敏感性一般,对支链淀粉含量较高的糯米和大米淀粉表现出较高的水解活性。将PtGA15应用于黄酒酿造,发现当糖化温度为50℃,糖化时间3 h时,酶添加量为200 U/g原料时,糖化液中还原糖和干物质含量最高,生产的黄酒酒精度为16.6%vol,相比对照组提高了30.7%,各项理化指标均符合国标的要求。     

木葡糖酸醋杆菌发酵黄酒糟酶解液产细菌纤维素的研究

该研究利用单因素比较法,分别考察了培养基组成、培养条件及黄酒糟酶解条件对木葡糖酸醋杆菌（Gluconacetobacter xylinus）发酵产细菌纤维素的影响。结果表明,木葡糖酸醋杆菌BC19-2产细菌纤维素的培养基组成为黄酒糟酶解液6%、红茶2 g/100 mL;培养条件为初始pH 6.0、培养温度30℃、接种量6%;黄酒糟酶解条件为酶解时间3 h,黄酒糟酶解液体积分数90%。在此优化条件下,细菌纤维素产量最高为26.5 g/L,且性能较好,为低成本的细菌纤维素生产奠定了基础。     

曲酒糟发酵生产燃料乙醇技术研究

曲酒生产过程中会产生大量的废弃物曲酒糟,如何综合利用,已成为白酒行业的工作重点。采用酸水解与酶水解法对曲酒糟进行高温水解,完善p H、预处理、温度及保温时间等工艺参数,利用耐高温α-淀粉酶、纤维素酶、糖化酶、酸性蛋白酶等多种生物酶系对曲酒糟中的纤维素进行发酵,并通过蒸馏得到燃料乙醇。实现了副产物的综合利用,解决白酒生产过程中的固体废物对环境的污染问题。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.